THE SECRET SPIES IN THE SKY - Imagery, Data Analysis, and Discussions relating to Military Space

SatTrackCam Leiden (Cospar 4353) is a satellite tracking station located at Leiden, the Netherlands. The tracking focus is on classified objects - i.e. "spy satellites". With a camera, accurate positional measurements on satellites of interest are obtained in order to determine their orbits. Orbital behaviour is analysed.

Yesterday evening, 28 Feb 2016 near 19:45 UT (20:45 local time), I shot the image above, one of two images showing the satellite passing near the Celestial pole. It is a short exposure of 2 seconds with the 2.8/180 mm Zeiss Sonnar lens on my Canon EOS 60D.

Below is the same image, but in black-and-white negative, showing the trail a bit better:

Kwangmyŏngsŏng-4 on 28 Feb 2016(click image to enlarge)

The object is very faint (probably near mag +7). It needs a rather big lens (the Zeiss 2.8/180 mm has a lens diameter of 6.4 cm), which unfortunately also means a small FOV. Over the two images, a total imaging arc of ~6 seconds, it however appeared to be stable in brightness with no sign of a periodicity due to tumble. So either it is not tumbling, or if it is tumbling at all it must be a very slow tumble.

Some 16 minutes earlier, near 19:28 UT, I also imaged the upper stage of the Kwangmyŏngsŏng/UNHA-3 rocket (2016-009B) that was used to launch the satellite. This object is brighter and shows a nice tumble resulting in periodic flashes. Below are crops from three images spanning 19:28:32 - 19:28:44 UT. The brightness variation is well visible (the bright star it passes in the first image is beta Umi):

A fit to the measured brightness variation over these three images shows several specular peaks at regular intervals, with a slightly asymetric profile:

click diagram to enlarge

The fit shown in red is the result of two combined sinusoids: a major period of 2.39 seconds with a minor period of 1.195 seconds superimposed (resulting in the slight asymmetry). Pixel brightness over the trails was measured with IRIS. The data were fitted using PAST.

UPDATE 1 March 2016:

I imaged both the UNHA-3 r/b and Kwangmyŏngsŏng-4 again in the evening of 29 Feb 2016. The sky conditions wer less good, and the pass was much lower in the sky. I used the 1.4/85 mm SamYang lens this time, to get a larger FOV in order to try to capture a larger arc.

KMS-4 was captured on four images (2 second exposures) between 19:19:17 - 19:19:34 UT. It was barely visible on the images, but again the brightness appeared to be stable over this 17 second time span.

The UNHA-3 r/b was also captured, and 3 images (5 second exposures) between 18:58:42 - 18:59:07 UT again showed a very nice flash pattern, fitting (like the observations of Feb 28) a flash period of 2.39 seconds:

click diagram to enlarge

The image below is a stack of these three images. The rocket stage moves from upper right to lower left in the image.

Wednesday, 24 February 2016

The MH17 discussion has become extremely messy. It is a highly politicized topic, with active disinformation campaigns and trolling from both the Russian and Ukrainian sides. It is sometimes hard to discern who is honestly seeking the truth, who is honestly seeking the truth but very naive with regard to sources, and who is actively involved in peddling propaganda and disinformation.

I have learned not to bother too much with trolls, but when they actively and tenaciously disseminate
disinformation and seriously flawed counter-arguments around one of my analysis, I reserve myself the right to a
rebuttal, just to set the record straight.

In a previous post I showed that a satellite image released by Russia, purported to be a Resurs P1 image from 17 July 2014 which claimed to show Ukrainian BUK's in a field near Zaroshchens’ke, is problematic. The viewing angles of the "BUK's" in the image do not appear to fit the satellite-to-location geometry, which only allows clearly oblique viewing angles between 45 and 57.5 degrees with the horizontal, from directions ranging from northwest via west to southwest (for more details, see my earlier post in question). I therefore urged caution with regard to these images.

My post has drawn fire on twitter, notably from a twitter user nicked "Masami Kuramoto". While the nick sounds Japanese, and the twitter account claims to be located in Germany, I have a strong suspicion that the entity behind it is Russian.

Kuramoto's chosen line of attack is by questioning the accuracy of the Resurs P1 orbital information which I used. That orbital information came straight from JSpOC (formerly known as "NORAD"), argueably this world's most reliable source of orbital elements. Kuramoto basically tries to advance a claim that the JSpOC tle's for Resurs P1 are either highly inaccurate or even deliberately doctored, and that the satellite in reality passed along a somewhat different trajectory (but with a similar pass time, to match the time listed in the images), thus advocating for the existence of an imaginary trajectory that allows to reconcile the imaging angles with the published images. In order for this to be possible, it is necessary to argue that the real orbit amounts to a significantly shifted orbital plane, i.e. a shifted RAAN value, compared to the JSpOC published orbit.

In an attempt to argue this position, Kuramoto suggestively quoted from the Space-Track terms of use, taking text out of context to insinuate that JSpOC tle's were not accurate for the task:

Let me first elaborate on what I pointed out in the tweets above. Kuramoto tried to capitalize on this warning in the Space-Track User agreement:

"A TLE AVAILABLE TO THE PUBLIC SHOULD NOT BE USED FOR CONJUNCTION ASSESSMENT PREDICTION"

This statement is relevant to close encounters (with the risk of collision) of two objects in space. What this statement simply means is that it is unwise to base decisions on debris avoidance manoeuvres solely on published tle's. In such cases, very small uncertainties matter. If one uses tle's produced for the epoch of today to make a prediction on a future position of two objects (say: 3 days from now), that prediction for a moment days from now will have a small uncertainty. SGP 4 after all is only a model. These uncertainties are negligible for other purposes, but for close encounter mitigation they matter. Satellites in Low Earth Orbit move some 7 km/s, so a 0.1 second uncertainty in the time of passing a particular point in orbit, hardly something to bother about under normal circumstances, amounts to a positional uncertainty along the orbit of 700 meter. This might not seem much and for other purposes 0.1 seconds and 700 meter is negligible, but for collision avoidance it matters: it might be the difference between a miss or a hit, certainly because the other object introduces a similar uncertainty (i.e., if both objects have 0.1 second uncertainty, the uncertainty in relative distance is 2 x 700 meter = 1.4 km. So if your analysis says they will safely pass 1.4 km apart, they might in reality collide instead. Or conversely, if your analysis says they will collide, the reality might be that they pass each other at a km distance rather than colliding).

In other words: the warning by JSpOC is only relevant to a very specific situation, and concerns uncertainties that are completely negligible for the subject at hand: the position of a satellite with respect to the viewing geometry of a location on earth. The more so because the latter assessment actually uses a tle with epoch very close to the the time of interest, unlike a collision avoidance assessment of a moment more removed in future. The uncertainty pointed out, in no way can change the viewing angles to the extend that it would solve the discrepancies I pointed out in my earlier post.

Now, this could have been a simple misunderstanding, based on a lack of knowledge and insight in the matter on Kuramoto's side.

Kuramoto however next took it to a new level and suggested that JSpOC might have deliberately altered the orbital elements for Resurs P1 post-fact:

@Marco_Langbroek I'm wondering what is the incentive for JSpOC to provide the public with accurate TLEs of Russian satellites... #MH17

The point is: if JSpOC would have done that, the simple reality is that many people working with these data would notice it. Satellites suddenly would be at different positions than where the JSpOC orbital data would put them. Our tracking network for example, frequently catches Russian satellites as byproduct of our tracking of classified objects. On these occasions we would suddenly note large positional errors in that case, and we would even start to see UNIDS (unidentified satellites, which always have our immediate attention) that next turn out to be Russian satellites in orbits not matching their JSpOC orbit. No way that would go unnoticed.

As for the suggestion that the elements were only retrospectively altered, Kuramoto was a bit shocked to learn next that several of us (including me) actually regularly archive the full JSpOC database of orbital elements. I do so several times each month (for July 2014, I for example have archived elements from July 14 and can compare these with elements for that date retrieved from the JSpOC archive today: they are the same, they have not been restrospectively altered). In a retrospective analysis, altering the elements starting at some given date (or only altering them around a given date) would show up as a sudden change in the elements as well.So no: such a plot is simply not realistic.

After this, Kuramoto nevertheless still wished to cast doubt on the JSpOC tle's:

This paper discusses what factors might introduce predictions that do deviate considerably from reality (with the focus again on the accuracy of data needed for orbital debris avoidance manoeuvres). One such case is when for example a position is based on a tle issued 4 hours ago, but the satellite in question meanwhile has actively manoeuvered to a new orbit. In that case, the predicted position indeed would be incorrect. Kuramoto (of course) tries to seize on that, but in doing so again shows a lack of insight in the matter. Whether a satellite (Resurs P1 in this case) had just manoeuvered can easily be checked: by looking at a series of tle's issued around the time of interest (17 July 2014, 8:32 UT in this case), a manoeuvre around the time of interest would be visible by a sudden change in elements.

For Resurs P1 around 17 july 2014, I did this check (Kuramoto obviously didn't). There is no such change, i.e. the satellite did not make a significant manoeuvre. This can be seen in the diagrams below which depict the evolution of the orbit (from JSPOC data over July 2014). A manoeuvre would show up as a clear discontinuity (a clear sudden change) in either perigee and/or apogee altitude, argument of perigee, inclination, Mean Motion and /or RAAN (and notably in RAAN for Kuramoto's argument to hold). Tampering with the orbital elements around 17 July by JSpOC would show up similarly, by the way. But none of this happens, as you can see below. So again, Kuramoto's next grasp at a straw, is futile, and by now his attempts to argue my analysis away are bordering the pathetic.

Again, his argument is largely irrelevant. The kind of deviations pointed out are very minor: a maximum error of 9.3 km in position at a given time really will not significantly change the viewing angles. That would need cross-track errors an order of a magnitude larger.

Saturday, 13 February 2016

The image above shows FIA Radar 4 (2016-010A), the payload of the NROL-45 launch of 10 Feb 2016, crossing through Corona Borealis around 6:26 am local time (5:26 UT) this morning (Feb 13) 3 days after launch.

It was about 6.5 seconds late on our very preliminary orbit. A new (hopefully) improved estimate of the orbit is here.

The SAR panels of the satellite do not seem to have deployed yet: the object is still relatively faint. This is normal: the panels are deployed a few days after the launch, based on patterns of earlier FIA Radar launches.

Thursday, 11 February 2016

Yesterday (10 Feb 2016) at 11:40:32 UT, the NROlaunched a new classified satellite from Vandenberg AFB, using a Delta-IV M rocket, under the launch designation NROL-45. The payload is the fourth FIA Radar (also known under the codename TOPAZ) and has the alternative designation USA 167 USA 267.

As with previous launches, our network of observers picked the payload up quite quickly. The first optical observations were made near 03:39 UT (11 Feb 2016), 16 hours after launch, by Cees Bassa in the Netherlands. Some two hours later, on the next pass, Leo Barhorst and me (both also in the Netherlands) observed NROL-45 as well, 18 hours after launch.

orbit of NROL-45, and position at time of photo(click to enlarge)

A first preliminary orbit is given here and here.
The satellite moves in a 122.98 degree inclined, retrograde orbit with
perigee near 1086 km and apogee near 1087 km. The retrograde orbit is a
clear indication that this satellite is a SAR (radar) satellite.

I did my observations under a very clear early morning sky, near 6:20 am local time. The NROL-45 payload was faint and could not be seen by the naked eye: this is normal during the first few days after launch. It will become brighter in a few days, likely because the SAR panel has then been unfolded.

With the launch of FIA Radar 4, there are now four FIA radars on orbit. Launch of a 5th one is expected in 2017. Of the current four satellites, the orbital configuration is such that the RAAN are 90 degree separated (see discussion by Ted Molczan here).

Sunday, 7 February 2016

This post is a brief update to my more elaborate post of earlier today here.

As I wrote in that post, western military tracking of the N-Korean satellite places it in an orbit with perigee at 465 km, apogee at 502 km and an orbital inclination of 97.5 degree.

It is interesting to compare this with the (English) radio announcement of the DPRK itself, which you can hear here.

In that bulletin, the orbit is given as having perigee at "494.6 km", apogee at "500 km", and an orbital inclination of "97.4" degrees.

Compare this to JSpOc data: 465 km, 502 km, 97.5 degrees.

The DPRK apogee perigee altitude does not match the JSpoC data, which gives a clearly lower apogee perigee at 465 km. This could in theory be due to initial errors in the JSpOC tracking data (the first few orbit determinations are always less accurate). But the magnitude of the difference is such, that I doubt that.

Assuming that the numbers in the DPRK radio bulletin are not based on actual North-Korean tracking data, but instead based on a pre-launch desired orbit, then maybe this could indicate that the satellite did end up in a slightly lower orbit than intended.

We'll see if the difference keeps standing with more western tracking data added...

[update:Jonathan McDowell suggested that perhaps the Koreans used another spheroid (earth shape) to refer to. I doubt that: not only would I expect similar discrepancies in the apogee altitude as well in this case (the apogee altitudes given by JSpOC and N-Korea are close), but moreover, 30 km is a large difference. I know of no ellipsoid that differs by as much as 30 km from the WGS84 ellipsoid]

[update 2:Bob Christy makes some very interesting remarks on his webpage, which also support the idea that orbit insertion did not go as intended].

My previous blogpost of Feb 4 (with an update on Feb 5) discussed the announced launch of a new North Korean satellite, Kwangmyŏngsŏng-4 (KMS-4), from Sohae satellite Launch center in the northwest of North Korea.

Yesterday (Feb 6), North Korea suddenly shifted the start of the launch window
one day forward, from February 8 to February 7 (local date). No reason
was given for this date shift.

It appears to have been successful, to the extend that they did successfully put an object into orbit, as the US military tracking network confirms. As the history with KMS 3-2 shows, whether the payload is really operational is another question and as for yet unanswered.

North Korean television announced the successful launch a few hours ago, in a bulletin in characteristic fashion, including images of the launch and of Kim Jong-Un watching the launch from Sohae:

I indicated a launch between 00:24 and 00:41UT (a 17 minute period out of a 5 hour window indicated by the North Koreans). The start of this window at 00:24 UT was based on the assumption of a launch at a similar solar elevation at Pyongyang as during the 2012 launch of KMS 3-2 (the end at 00:41 UT was based assuming a launch exactly 52 hours after Pyongyang sunrise rather than at a similar solar elevation to 2012).

The actual launch occurred at 00:29 UT, only a few minutes from the start of the window which I indicated. It corresponds to a solar elevation of 18.0 degrees at Pyongyang (the 2012 launch happened at a solar elevation of 17.5 degrees).

Orbit

The first orbital elements from JSpOC show two objects in orbit as a result of the launch: an A-object (catalogue number 41332, 2016-009A) and a B-object (catalogue number 41333, 2016-009B). The A-object is likely the satellite.

The A-object moves in a 97.5 degree inclined, 465 x 502 km sun-synchronous polar orbit with an orbital period of 94.3 minutes. The satellite makes daily morning passes around ~9h am. It has a repeating ground-track every 4th day. This is consistent with a remote-sensing role.

The orbit is somewhat lower and more circular than that of North Korea's previous satellite, KMS 3-2, which was initially placed in a 495 x 588 km orbit. Like the 2012 launch, North Korea had to perform a dogleg manoeuvre to attain an orbital inclination of 97.5 degrees after launching due south from Sohae (see discussion in my previous post).

The second, B object is the spent upper stage of the rocket, and is moving in a 433 x 502 km orbit.

The map below shows the satellite's ground-track during the first 5 orbits after launch:

North Korea's ruler Kim Jong-Un watched the launch from the grounds of the Sohae Satellite Launch Center. In the image below, he is observing the rocket ascend from a viewing platform which appears to be in front of the oval building that was erected at Sohae between March and July 2014 (see this satellite photo analysis on the 38 North blog).

A few more stills of the launch, taken from the North Korean tv broadcast:

The launch of Kwangmyŏngsŏng 4 is the second time that the North Korean rocket program was successful in placing an object in orbit. North Korea itself claims a number more successful launches, but these failed according to western sources as no objects were tracked in orbit.

Current spatial separation of the orbital planes of KMS 3-2 and KMS 4

Note added 18:00 UT, 7 Feb: a brief update noting inconsistencies between early western tracking data and a DPRK announcement is here.

Following a nuclear test on January 6th (claimed to be a small H-bomb by the North Koreans, although western observers doubt this), North Korea has announced the launch of a satellite, with issued Broadcast Warnings pointing to a launch between February 8 and 25. The launch period starts at the date of the 70th anniversary of the Provisional People's Committee.

Satellite image analysts at the 38 Northwebsite had already been documenting preparations for a launch at the launch site in Sohae in January. Over the past 3 year, North Korea had been making several improvements to its launch installations, building various new structures on the site.

Meanwhile, the upcoming launch has western nations and neighbouring states concerned. Especially Japan has expressed very strong concerns about the launch. Like they did in 2012, they have threathened to shoot the rocket down if it seems to be headed for Japan. That is unlikely to happen though.

[added note: the original letter of North Korea to the Int. Maritime Organization on which this navigational warning is based, is here].

Area A is the splash-down area for the first stage, area B for the
fairings, and area C for the second stage (the third stage will remain
on-orbit after launch). Plotting these on a map (red boxes in map below) reveals them to be on a north-south line with azimuth ~180 degrees (yellow line), avoiding the main islands of Japan:

(click map to enlarge)

The ~180 degree launch azimuth points to a satellite launch into Polar orbit, very similar to the launch direction of North Korea's previous satellite, Kwangmyŏngsŏng (KMS) 3-2 (2012-072A) three years ago (a nice background piece on that launch by Brian Weeden discussing "satellite launch or missile test?" can be found here). Compare my map above to the map constructed from the NOTAM's for the KMS 3-2 launch in 2012 on Bob Christy's website, [edit: and see also the comparison of 2012 to 2016 in this blogpost by Melissa Hanham on the Arms Control Wonk blog].

As was the case with their previous KMS 3-2 launch, the intended satellite orbit is, given the launch direction, likely a sun-synchronous orbit with an orbital inclination of 97 degrees. The launch direction due south rather than directly into a ~97 degree inclined orbit has been chosen to avoid overflying (and debris landing on) the territories of China and Taiwan during the ascend phase. In order to reach a true sun-synchronous orbit with inclination ~97 degrees, it necessitates a dog-leg manoeuvre of the third stage with payload during the final phase of the ascend to orbit (blue line in map above, approximate only). Orbit insertion of the payload will be about ten minutes after launch, just before reaching the Phillipines.

Assuming the resulting orbit of the satellite will be similar to that of KMS 3-2 in 2012 (perigee ~495 km, apogee ~588 km, inclination 97.4 degrees), the trajectory of its first revolution around earth will look something like this (yellow dot shows satellite position one hour after orbit insertion):

(click map to enlarge)

The launch window is 17 days long, and runs daily from 22:30 to 03:30 UT, according to the Broadcast Warning. The daily 22:30-03:30 UT window is similar to that of the KMS 3-2 launch in 2012. It runs from local daybreak to just short of local noon, indicating a desire for an orbital plane resulting in morning passes.

In 2012, KMS 3-2 was launched at 00:49:49 UT, almost exactly two hours after Pyongyang sunrise (22:50 UT). This suggests (if a similar orbital plane with overfly times at ~9h am local time is aimed for) that the current launch might happen somewhere between 00:24-00:41 UT, depending on whether the aim is for launch at a similar solar elevation (then it will be close to 00:24 UT) or merely two hours after Pyongyang sunrise (then it will be close to 00:41 UT). However (see the next paragraph), the timing of the 2012 launch also seems to have been (at least partially) dictated by a suitable window lacking overflights by western reconnaissance satellites. As for the date, I hesitate to prophecy on this, but I wouldn't be surprised if they go - weather permitting- for February 8, the first day in the 17-day window.

It appears that the North Koreans carefully chose their launch moment in 2012. US military sources already had claimed shortly after the launch that North Korea had played a ruse on them and evidently knew when western optical imaging satellites had (and had not had) view of the launch installations. This seems to be confirmed by my independent analysis of that launch from December 2012, which showed that the North Koreans used the very end of a longer-than-usual one-hour gap in IMINT coverage of the launch site to launch. And as I wrote in that blog post, a North Korean IP address had been looking for orbital elements of US optical and radar satellites on this very blog just days before the launch.

The ruse was apparently designed to keep the USA, Japan and South Korea in the dark about the launch moment until the actual moment of launch itself (which would be registered by SBIRS and DSP satellites), as a counter-measure to give potential intercepts of the rocket as little advance preparation time as possible.

It would be difficult for North Korea to repeat such a ruse these days, as the number of western optical and radar reconnaissance satellites has grown ubiquitously in the past three years. Assuming launch near 00:40 UT (two hours after sunrise), the most promising dates (from the perspective of relative lack of western IMINT coverage) are three dates in the first week of the launch window: February 8, 10 and 14. But maybe North Korea is confident enough this time, following the experience with KMS 3-2, to not bother with western IMINT coverage at all.

Tuesday, 2 February 2016

Time to go back to basics. The photo above is part of an image I shot in the evening of January 20-21, 2016. It shows a number of commercial geosynchronous satellites and two classified satellites: AEHF 2 and SBIRS-GEO 2.

This image was shot from Leiden center using a Canon EOS 60D and a Zeiss Sonnar 2.8/180 mm lens and 15 seconds exposure (ISO 1000). It shows an approximately 2.5 degree wide field in Hydra, just east of alpha Hydra. The sky was extremely transparent, and to my surprise a waxing moon in the sky was no real hindrance: conditions I do not encounter often!

Most prominent on the image (a crop out of a larger image) is the commercial Astra 1 group, a group of four satellites well known to European owners of satellite tv dishes. Just north of the group is AMOS 5, an Israeli commercial communications satellite. It suffered a malfunction on 21 November 2015, as a result of which all contact was lost.

Also visible in the image are the commercial satellite Arabsat 5C and the Chinese satellite Tianlian 1-03. The latter satellite is a Tracking- and Data Relay satellite that plays a similar role to the US TDRS satellites. The Tianlian satellites are specifically meant to relay data to and from Chinese crewed Shenzou spacecraft.

Two classified US satellites are visible in the image.

On the right is AEHF 2 (2012-019A), the second Advanced Extremely High Frequency military communications satellite. The AEHF system is a replacement for the older Milstar system, and use of this US system is shared by the military of a number of countries, at this moment the UK, Canada, and my own country, the Netherlands. It is eventually to consist of 6 satellites, of which 3 have been launched as of early 2016. The satellites have been designed to be resilient to jamming and intercept efforts.

On the left is SBIRS GEO 2 (2013-011A), the second geostationary satellite in the Space Based Infra Red System, a series of US infra-red Early Warning satellites meant to detect missile launches. I discussed this system in detail in several recent blogposts, as this system might have played a role in potentially detecting the missile that shot down Malaysian Airlines flight MH17. Indeed, the satellite imaged here, SBIRS GEO 2, is one of the SBIRS satellites that had sight on the Ukraine at that time.

About the Author

Dutch, 47, PhD, stone age archaeologist, meteoriticist, satellite tracker, meteor observer, asteroid discoverer. Consultant in a Space Situational Awareness project with the Space Security Center of the Royal Dutch Air Force and Leiden Observatory. As an invited expert I advised members of Dutch Parliament about military satellite systems and their locations during a 2016 foreign affairs committee hearing about the MH17 disaster.
Asteroid (183294) Langbroek was named after me. In 2012, I received the Dr. J. van der Bilt Prize of the Royal Dutch Astronomy Association (KNVWS) for my work on meteors, asteroids and satellites.
Opinions expressed on this blog are entirely my own.
You can find me on Twitter via @Marco_Langbroek

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Excerpt from United Nations resolution 2222 (XXI)

Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies

In order to promote international co-operation in the peaceful exploration and use of outer space, States Parties to the Treaty conducting activities in outer space, including the moon and other celestial bodies, agree to inform the Secretary-General of the United Nations as well as the public and the international scientific community, to the greatest extent feasible and practicable, of the nature, conduct, locations and results of such activities. On receiving the said information, the Secretary-General of the United Nations should be prepared to disseminate it immediately and effectively.